A LINFOX truck driver who made distasteful comments about his Muslim boss and sexual comments about a female manager on Facebook was unfairly dismissed, Fair Work Australia's (FWA) appeal bench has found.

The industrial umpire today upheld an earlier decision by FWA Commissioner Michael Roberts after the trucking company appealed his decision supporting the driver's unfair dismissal case.

Linfox had terminated the man's employment in May last year on the grounds of serious misconduct.

It said comments he posted about two managers on his Facebook page were offensive, derogatory, discriminatory and included suggestions of dishonest and underhanded conduct, and comments of sexual misconduct.

Commissioner Roberts said the man believed his Facebook account, set up by his daughter and wife, had the highest available privacy settings.

He also said while the driver had made distasteful comments in a forum about the death of a Muslim terrorist, they couldn't be characterised as a personal attack on one of his managers, who is a practising Muslim.

A remark referring to his manager as a "bacon hater" was in poor taste, but not derogatory or intended to be hurtful.

Comments of a sexual nature posted about a female manager were outrageous but most of the remarks had been made by others in a Facebook conversation.

The original ruling also said Linfox did not have a policy on the use of social media by employees in an era when many companies had detailed policies in place to guide employees.

FWA had ruled the man was not guilty of serious misconduct relating to the company's reasons for terminating his employment and his dismissal was harsh, unjust and unreasonable, and Commissioner Michael Roberts ordered he be reinstated.

Linfox appealed on the grounds Mr Roberts had erred in several respects in making the orders for reinstatement and compensation.

It said Mr Roberts had given no or insufficient consideration to relevant facts and made errors of fact, with an undue emphasis placed on a purported right to free speech.

In dismissing the appeal, the appeal bench said Linfox had pursued it "on the basis of seeking a different outcome ... based on overstated concerns as to the nature and effect of the posting on the applicant's Facebook page".

The appeal bench said the driver had an extremely good employment record over 22 years and his comments were never intended to be communicated to the managers concerned.

It did not support Commissioner Roberts' order for Linfox to pay the man lost wages.